Interpretive Summary: This paper discusses on-farm research done to test the performance of a new catfish egg incubator, the “See-Saw”. In that largest on-farm hatchery research project yet conducted it was determined that the See-Saw incubator can effectively incubate up to 45 lb of spawns (670,000 eggs), up to three times as many eggs as traditional paddle-type incubators while using less than half the water, providing a savings in floor space, water and energy use.

Technical Abstract:
Channel catfish spawns are typically incubated in ¼-in mesh baskets suspended in water that is agitated with paddles positioned between baskets. We tested a new vertical-lift incubator (the “See-Saw”) to incubate channel catfish spawns. Previous research demonstrated that when loaded with spawns at rates higher than recommended for traditional paddle-type incubators, as often occurs during the peak of the spawning season, survival to swim-up stage was significantly (2.3x) higher in the See-Saw than in traditional incubators. This project examined the effect of spawn loading rates on hatching efficiency of the See-Saw. In Study 1 See-Saws were loaded with 15.0 ± 0.1 lb (219,825 eggs), 30.1 ± 0.1 lb (446,055 eggs), 45.1 ± 0.1 lb (668,206 eggs), or 60.1 ± 0.1 lb (891,157 eggs) of spawns per trough. Water flow averaged 2.1 gpm, roughly 40% the rate recommended for paddle-type incubators. Swim-up fry production increased proportionally to egg loading density up to 45 lb/trough, with the 15, 30, and 45 lb troughs producing 132,658, 263,828, and 429,422 swim-up fry, respectively. However, the 60 lb treatment produced only 417,237 swim-up fry. Survival to swim-up stage in the 15, 30, and 45 lb treatments averaged 60 ± 9%, 59 ± 6%, and 64 ± 4%, respectively, similar to values reported in commercial hatcheries (60%), but survival to swim-up in the 60 lb treatment averaged only 46 ± 8%. In Study 2, addition of liquid oxygen to See-Saws loaded with 36 spawns (approximately 45 lb) increased the DO concentration by 4.0 ppm (125% air saturation) but had no effect on survival to swim-up. The See-Saw incubator can effectively incubate up to 45 lb of spawns (670,000 eggs), up to three times as many eggs as traditional paddle-type incubators while using less than half the water, providing a savings in floor space, water and energy use.